292 Professor E. B. Poulton on Mimetic Forms of 
the Victoria Nyanza. It is unknown and_ probably 
entirely wanting from the sub-species merope on the west 
coast, but it may perhaps occur at the extreme eastern 
development of the sub-species in Uganda. Its dis- 
tribution is thus co-extensive with that of its Danaine 
models the forms of Amawris echeria and albimaculata. 
(a) Hvidence of diaposematic mimicry between the cenea @ /f. 
of P. dardanus and two species of the Danaine genus 
Amauris. 
It has been shown on p. 286 that the squarish shape of 
the large pale patch on the hind-wing of the female forms 
of dardanus is extremely ancestral, and the question arises 
as to whether Amauwris echerta and albimaculata have not 
mimicked and indeed exaggerated this feature in the 
Papilio which in other respects has mimicked them. There 
are many reasons in favour of diaposematic relationship 
between Danaine and Papilio, The squarish patch in the 
two species of Amau7is, although far more marked than in 
the cenea form, is in all probability a recent development. 
It shows remarkable synaposematic sensitiveness, losing 
much of its characteristic sharpness and angularity in the 
presence of other species of the same genus. This change 
may be seen by a glance at Mr. 8S. A. Neave’s Plate 1X 
in the present volume. Amauwris albimaculata (f Fig. 2a, 
? Fig. 3a) shows this change in the presence of Amauwris 
psyttalea, torm damoclides, ? Fig. 2,¢ Fig. 3. Compare the 
shape of the patch in the two sexes of albimaculata, with 
that of the same species from Natal far beyond the influence 
of damoclides,—f Fig. 4,9 Fig. 5. Amauris echeria is also 
changed in the same direction by the presence of the 
same model, as may be seen by comparing ¢ Fig. 2b and 
2 Fig. 3b under the influence of damoclides (f Fig. 2, 9 
Fig. 3), with the same species from Natal—f Fig. 6, 9 
Fig. 7. Amauris lobengula (Plate XXII, Fig. 1), closely 
allied to A. echeria and probably ancestral to it, because 
less peculiar in the genus, possesses a larger hind-wing 
patch in which the square shape is not nearly so marked. 
It is in fact almost precisely similar in shape to that of 
the triment form shown on Plate XIX, Fig. 1, and the 
hippocoon on Plate XVIII, Fig. 2. The exaggeration 
of the feature in Amauris albimaculata and echeria 
is no reason against the hypothesis that it has been derived 
by mimicry. In the great majority of the forms of Acrwa 
